Means for Preventing Tools from Being Pulled Out from Tool Holders with a Tool Holding Fixture

ABSTRACT

The invention relates to a tool holder with a tool holding fixture, in particular a clamping chuck such as a contracting chuck, a draw-in collect chuck, a hydraulic expanding chuck and a high-precision chuck, and a shank of a tool, in particular a rotary tool, accommodated in it, wherein the tool holder contains a means for preventing the tool from being pulled out, locking it against axial displacement. This pull-out preventing unit comprises at least one locking element and at least one locking groove, which corresponds to the said locking element, receives it and interacts with it in a positively locking manner. In this case, both the locking element and the locking groove are formed at least partly in the manner of a ball head. Preferably, the tool has the locking grooves. On account of preferably spirally arranged locking grooves along the cylindrical shank of rotary tools, the direction of pitch of which grooves corresponds to the direction of the grooves of the tool, axial locking of the tool is obtained, so that the tool cannot be axially displaced from the tool holder during operation. In addition, force-exerting elements are arranged, with the effect of making the tool lie against the pull-out preventer without play after shrink-fitting.

The present invention relates to tool holders comprising a tool holdingfixture, in particular shrink fit chucks and other chucks for receivingrotation tools according to the preamble of patent claim 1.

Tool holders with clamping chucks, in particular shrink fit chucks, arewell known. They are being used for clamping tubular tools, turningtools, milling tools, reaming tools, and grinding tools, and similarthrough a thermally induced shrink process. Typically, such shrink fitchucks are thermally heated by an inductive shrink system, whereby theinner diameter of the shrink fit chuck is expanded. When the innerdiameter is enlarged, a tool to be clamped is inserted into the shrinkfit chuck, wherein the ratio of the inner diameter of the shrink fitchuck to the shaft diameter of the tool is configured, so that the toolis clamped torque proof in the shrink fit chuck after subsequent coolingof the shrink fit chuck.

From WO 01/89758 A1 it is known to inductively heat the sleeve sectionby means of an annular coil assembly, substantially surrounding thesleeve section in a coaxial manner. The coil assembly is connected to ahigh frequency AC generator and induces Eddy currents in the metalsleeve section, which heat the sleeve section. In order to avoid scatterflux and to concentrate the magnetic flux, magnetic flux concentrationelements made of soft magnetic electrically substantially non-conductivematerial, like e.g. ferrite or similar, are disposed at the faces and atthe outer circumference of the coil assembly, which direct the magneticflux generated by the coil assembly to the sleeve section of the toolholder, and in particular into the portion of the free end of the sleevesection.

The problem with tool holders comprising clamping chucks for rotatingtools which comprise cylindrical receiving shafts is the axial migrationof the rotation tool along the rotation axis of the clamping chuck outof the clamping chuck during operation. Said axial migration of therotating tool is caused by vibrations, which occur while machining thework piece with the rotating tool. Due to this detrimental effect, thework pieces cannot be machined precisely and according to theirdimensional specifications. Furthermore, canting the rotating tool inthe work piece or even in the clamping chuck receiving the work piececan lead to dangerous accidents. Under non-favorable conditions, therotating tool can even leave the clamping chuck of the tool holderduring operation in a marginal situation, and thus create a great hazardfor the machine operator.

It is thus the object of the present invention to provide a tool holderwith a clamping chuck, in particular a shrink fit chuck or similar, inwhich an axial migration of the rotating tool, like a spiral drill,profile drill, screw drill including tap, end facing drill, cutter,etc., is not possible during operation, but in which the rotating toolis mounted torque proof, as well as also axially fixated with respect tothe rotation axis without any migration out of the chuck.

This object is accomplished according to the invention through thecharacterizing features of patent claim 1, wherein advantageousimprovements of the invention are provided by the features of thedependent claims.

According to the invention, a tool holder according to the inventioncomprises a pullout preventer for the tool, which prevents axialmigration of the tool out of the tool holding fixture. Thus, the pulloutpreventer comprises at least one locking element and at least onelocking groove corresponding thereto, receiving the locking element,which interact through form locking. Thus, the locking element and thelocking groove are at least partially configured with a ball headprofile, wherein either the clamping chuck comprises the lockingelements and the tool comprises the locking grooves, or vice versa.Furthermore, thus the locking grooves, which are disposed starting atthe face side, either on the tool shaft, or in the tool holder, can beprovided expanded with reference to the groove width, in order to thusfacilitate easier insertion of the tool into the tool holder.

In a particularly preferred embodiment, the tool holder comprises atleast two rotatably supported balls on the tool holder side, wherein onthe side of the rotation tool at least two locking grooves at the shaftof the rotation tool, which correspond to the balls, interact in a formlocking manner. The two locking grooves are thus preferably providedlike a thread at the cylindrical tool shaft starting at the face side ofthe cylinder shaft along the circumferential surface of the cylindershaft. Said locking grooves disposed on the circumferential surface ofthe cylinder shaft of the rotation tool are provided with a left pitchdirection for tools with a left groove and are provided with a rightpitch direction for rotation tools with a right groove. Thus, thelocking grooves can also be configured in axial direction and thusparallel to the rotation axis, wherein this still provides safetyagainst rotation for the tool.

In order to clamp the rotation tool according to the invention, likee.g. spiral drills, profile drills, screw drills including taps, endfacing drills, cutters, and arbors for other tools etc. in the clampingchuck according to the invention, e.g. the shrink fit chuck of the toolholder, the induction coil is initially turned on in the shrink fitchuck, this means the induction coil is connected to high frequency ACpower. Due to the Eddy currents occurring in the sleeve section of thetool holder generated by induction from the coil surrounding the toolholder, the sleeve section is quickly heated up, so that it expandsthermally, and thus the inner diameter of the receiver opening isenlarged. Now, the rotating tool can be inserted into the receiveropening with its shaft. The face of the rotating tool thus reaches theballs protruding into the inner cavity of the receiver opening and stopsthere. Depending on the pitch direction of the locking grooves of therotating tool, said tool is now rotated counterclockwise or clockwisewith respect to the rotation axis, so that the balls can engage the ballreceiving grooves. Further rotation forces a helical rotation, and thusan axial pull-in movement of the rotation tool into the shrink fit chuckor similar, until the face of the cylindrical shaft contacts the shrinkfit chuck or until the balls have reached their final position in theball receiving locking grooves. The induction coil can be turned offnow. Due to the quick cooling which occurs now, the shrink fit chuckshrinks back again to its original size, which connects the cylindricalshaft torque proof with its circumferential surface to the innercircumferential surface of the receiver opening of the shrink fit chuckwith a press fit. Since the rotation direction of the locking groovescorresponds to the rotation direction of the rotating tools during theoperation of the tool also under high load, that means, under highcutting resistance of the work piece and under large feeds of the toolor of the tool table, an axial migration of the rotation tool along therotation axis out of the chuck cannot occur anymore. Through theinteraction of the balls in the tool holder with the ball profilelocking grooves in the tool shaft, and the thread configuration of saidlocking grooves, an axial locking is accomplished. Said axial lockingcan only be released by rotating the rotating tool against the operatingdirection of the rotating tool and pulling it out of the clamping chuck.A rotation performed against the operating direction of the rotationtool during operation is thus, however, not possible when machining thework piece with the rotating tool. Furthermore, said rotating movement,due to the torque proof press fit, is not possible during operationeither. Thus, the rotating tool cannot move out of the shrink fit chuckor similar.

Thus, the machining remains precise, and the dimensions can be keptwithin the required tolerances. Since axial migration out of the chuckis prevented by the present invention, production can be run efficientlyand more economically, since, compared to state of the art tool holderswith clamping chucks, very little scrap is produced. Additionally, thusanother cause for accidents and thus accident risk for the machineoperator is excluded.

Instead of the rotatable balls held in a press support in the clampingchuck, also cylindrical pins with a partial or half sphere can be usedat one of the faces. These are disposed in the support bore hole insteadof the balls, wherein these pins either require a protruding shoulder,so that the cylindrical pin does not fall into the inner cavity of thereceiver opening, or an outer thread which corresponds to the innerthread of the support bore hole. Using balls has the advantage comparedto using cylindrical pins with a partially spherical or semi-sphericalhead that inserting the rotation tool is easier compared to cylindricalpins, since the balls are rotatably supported and cannot cant relativeto the cylindrical shaft. Balls can also be held in the respectivesupport bore hole using a threaded pin. Thus, the threaded pin comprisesa configuration receiving the ball even at its face, e.g. shaped as apolygonal recess or as a ball shaped depression or similar. Instead ofthe threaded pin, also mating pins, bolts or similar can be used.

The pullout preventer according to the invention for tools, inparticular for rotation tools in tool holders, with a tool holdingfixture is suited in particular for clamping chucks, like e.g. draw-incollet chucks, high precision chucks, hydraulic expanding chucks, andshrink fit chucks.

Advantageously, depending on requirements, the locking grooves in thecircumferential surfaces of the shaft of the tool are configureddifferently. Thus, the locking grooves can comprise a different lockinggroove path beginning on the face side. It can be helical, L-shaped,curved, or formed from composite paths on an enveloping surface of acylinder, which is straight in portions and/or curved. In particular, ina helical locking groove path, the direction of rotation has tocorrespond to the direction of rotation of the grooved tool. This means,for a left grooved tool, the helical locking groove has to have a leftpitch direction; for a right grooved tool, on the other hand, thelocking groove has to have a right pitch direction. Therefore, there isa locking effect of the pullout preventer.

In another embodiment, the shaft of the tool comprises an outer threadat the end, and the tool holding fixture of the tool holder comprises aninner thread corresponding thereto. In this case, the pullout preventingfeature is implemented using the outer thread at the tool, which has aleft pitch direction for a left grooved tool, and a right pitchdirection for a right grooved tool. In this embodiment, locking elementsand locking grooves become obsolete.

In a particularly preferred embodiment, the support bore holes, whichreceive the locking elements, are configured preferably from the outercircumferential surface of the tool holder until into the inner cavityof the tool holder receiving the tool. Thus, said support bore holes canbe configured perpendicular to the rotation axis of the tool holder andso that they intersect the rotation axis, and/or tangentially adjacentto the inner circumferential surface of the cavity which receives thetool. Preferably, the longitudinal axes of the support bore holes areconfigured at the same angle, and in particular in a plane perpendicularto the rotation axis of the tool.

In another particularly preferred embodiment, in particular for toolholders with shrink fit chuck, balls are supported as locking elementsin a ball retainer. Thus, the support bore holes for the respectiveballs in the ball retainer comprise a smaller bore hole diameter withrespect to the inner circumferential surface than the diameter of thesupport bore hole. Thus, the balls cannot fall to the inside into theinterior of the tool holder, but they only reach over the inner portionof the ball retainer. The ball retainer can thus either be inserted as aseparate component in an interlocking manner into the inner cavity ofthe tool holder, or it can be machined into a sleeve. Thus, the sleevecomprises the respective support bore holes with the smaller supportbore hole diameters located towards the inner cavity. The sleeve canthus be pressed or shrunk into the inner cavity of the tool holdingfixture, welded to the tool holder, held in a form locking manner byadditional threaded pins, and/or fixated with locking elements andlocking grooves at the sleeve, as they are described according to theinvention at the shaft of rotation tools.

In a particularly preferred embodiment, in particular for shrink fitchucks, the pullout preventer comprises an additional device, whichfacilitates a support of the tool by the pullout preventer withoutclearance. Thus, the tool is pressed into the tool holding fixture outof the tool holder by a force imparting element, which is disposed e.g.concentric to the rotation axis of the tool at the bottom of the borehole of the tool holding fixture. Thus, the pullout preventer contactsthe tool without clearance. Since even a small clearance between thepullout preventer and the tool allows the tool a certain mobility, whichcan also lead to damages of the tool edges. In particular, compressionsprings in the form of coil springs, conical springs, disk springs, anddisk spring packets, and/or elastic or rubber elastic elements can beused as force imparting elements.

In another particularly preferred embodiment of a tool holder with aminimum volume lubrication, said tool holder comprises at least onetransfer piece for the minimum volume lubrication, which comprises atleast one, preferably plural channels for the pressure buildup or forthe pressure compensation. For such a tool holder with such a transferpiece, additional protection may be applied for separately from thepullout preventer. The transfer piece preferably provided as a tube,which can be also comprised of plural components, is preferably formedwith a radial flange, and preferably movably received and guided in abore hole disposed in the tool holder. The tube, which can also comprisedifferent cross section profiles, is preferably supported in the toolholder preloaded by a coil spring, wherein the cylindrical shaft of thetube preferably reaches through the coil spring. Certainly, also otherforce applying elements, like tension spring, conical spring, diskspring, and/or elastic elements and their combinations are possible. Thecoil spring is preferably disposed between the radial flange of the tubeand e.g. a bottom stop in the tool holder, whereby the tube is supportedpreloaded relative to the tool holder. The transfer piece is preferablysupported in the bore hole, so it is sealed. Thus, the tool holdercomprises at least e.g. one shaft seal and/or additional seal elements,like seal rings, seal lips, etc., concentric to the bore hole for thetransfer piece or for the tube, wherein said seal elements can also bedisposed in the tool holder and/or at the transfer piece or at the tubeitself. The channels provided in the form of pass-through bore holes, inparticular with circular cross section profile, wherein also other crosssection profiles are possible, are preferably disposed in the radialflange of the transfer piece, so that the transfer bore holes in thetransfer piece are connected to the transfer bore hole in the radialflange of the transfer piece. Along the cylindrical circumferentialsurface of the radial flange of the transfer piece, a radial recess isdisposed. Therein, an annular membrane is embedded preferably in a formlocking manner, which corresponds to the radial cutouts and which ispreferably shaped as a section of an enveloping surface of a cylinder.Thus, the circumferential surface recess, in particular provided as agroove, and also the cross section of the membrane embedded in thegroove preferably corresponding thereto, can e.g. comprise or a partialball head profile or other profiles. The annular membrane is preferablyformed from an elastic material, in particular from a rubber elasticmaterial, but also other materials are possible, like e.g. carbon fibermaterial, plastics, Teflon and flexible metals. The channels for thepressure compensation or for pressure venting or pressure buildup arethus in particular connected to the membrane and to the inner cavity ofthe transfer piece. When pressure is built up in the tool holder, themembrane thus cambers in radial direction, and thus attaches to thecircumferential surface of the receiver bore hole of the tool holder.Thus, the transfer piece is locked against axial movement.

Subsequently, embodiments of the invention are described with referenceto schematically depicting figures, in which:

FIG. 1 shows a sectional view of the tool holder according to theinvention, comprising a shrink fit chuck with a separate end millcutter, which is provided with locking grooves and which is not yetclamped;

FIG. 2 shows a sectional view of the tool holder according to theinvention, comprising a shrink fit chuck with an end mill cutteraccording to the invention clamped therein;

FIG. 3 shows a sectional view of the tool holder according to theinvention, comprising a shrink fit chuck with an end mill cutteraccording to the invention clamped therein;

FIG. 4 shows a sectional view of the tool holder according to theinvention, comprising a high precision chuck and an end mill cutteraccording to the invention clamped therein;

FIG. 5 shows a sectional view of the tool holder according to theinvention, comprising a hydraulic expanding chuck with end mill cutteraccording to the invention clamped therein;

FIG. 6 shows a sectional view of the tool holder according to theinvention, comprising an end mill cutter according to the inventionclamped therein, where the tool comprises an exterior thread, which isthreaded into a corresponding interior thread of the tool holder;

FIG. 7 shows a sectional view of the tool holder according to theinvention, comprising balls as locking elements, which are secured bythreaded pins;

FIG. 8 shows a sectional view of the tool holder according to theinvention, comprising balls as locking elements, which are secured bythreaded pins, where the balls are partially recessed into the threadedpins;

FIG. 9 shows a sectional view of the tool holder according to theinvention, comprising balls as locking elements which are secured bycylindrical pins in the press fit;

FIG. 10 shows a sectional view of the tool holder according to theinvention, comprising a one-piece locking element, which is a threadedpin with a ball shaped embossing at one of its faces;

FIG. 11 shows a sectional view of the tool holder according to theinvention, comprising one-piece locking elements, which are cylindricalpins with a ball shaped embossing at one of the faces in a press fit;

FIG. 12 shows a sectional view of the tool holder according to theinvention with balls in a separate ball retainer and a sleeve adjacentthereto;

FIG. 13 shows a sectional view of the tool holder according to theinvention, comprising balls, which are disposed in a ball retainer,which is machined into the sleeve, wherein the sleeve is pressed in orshrunk in;

FIG. 14 shows a sectional view of the tool holder according to theinvention from FIG. 13, wherein the sleeve is welded to the tool holder;

FIG. 15 shows a sectional view of the tool holder according to FIG. 13,where the sleeve is mechanically fixated by threaded pins with a conicaldome;

FIG. 16 shows a sectional view of the tool holder according to theinvention, comprising a slotted sleeve, which receives the balls, andwhere the sleeve is provided with locking grooves and held at the toolholder by additional balls and threaded pins;

FIG. 17 shows a sectional view of the tool holder according to theinvention, comprising a conical spring for a pullout preventer withoutclearance;

FIG. 18 shows a sectional view of the tool holder according to theinvention, comprising a length adjustment screw, which is formed fromrubber elastic material;

FIG. 19 shows a sectional view of the tool holder according to theinvention, comprising a length adjustment screw, which comprises anelement made of rubber elastic material;

FIG. 20 shows a sectional view of the tool holder according to theinvention, comprising a minimum volume lubrication, balls as lockingelements, and a membrane made of rubber elastic material;

FIG. 21 shows a sectional view and a side view of the tool holderaccording to FIG. 20 according to the invention with a tangentialdisposition of the locking elements;

FIG. 22 shows an enlarged illustration of a portion of FIG. 20 of thetool holder according to the invention with the membrane and a pressurechannel in the transfer piece.

FIG. 1 shows the tool holder 1 schematically in a sectional view and anexemplary end mill cutter 2, which are disposed relative to one anotherwith respect to a rotation axis 3. The tool holder 1 thus comprises atleast two, preferably three or four, balls 4. The ball is thus disposedin a support bore hole 5, which is disposed perpendicular to therotation axis 3, and thus to the longitudinal axis in the sleeve section6 of the tool holder 1. Said support bore hole 5 is a pass-through borehole and extends from the outside of the sleeve section 6 to the innercircumferential surface of the receiver opening 7, which is disposedconcentric with the rotation axis 3 in the tool holder 1. The frontsupport side 8 of the support bore hole 5 is provided in the shape of aspherical cap or configured according to the ball shape of the ball 4,so that the ball 4 partially protrudes into the inner cavity of thereceiver opening 7. The ball 4 is held by a threaded pin 9 in itsforward position, thus in a position protruding into the inner cavity ofthe receiver opening 7. Thus, the support bore hole 5 comprises an innerthread corresponding to the outer thread of the threaded pin 9. Thus,the length of the threaded pin 9 does not protrude beyond the outersurface of the sleeve section 6. The threaded pin 9 thus comprises ahexagonal hole 10 for an Allen wrench. The end mill cutter 2 comprisesthe helical locking grooves 13, 14 on its cylinder shaft 11 proximal tothe face 12. They comprise a ball shaped profile, which corresponds tothe ball shape of the ball 4. In order to completely clamp the end millcutter in the tool holder, the tool holder has to be rotated accordingto the rotation direction 15 during insertion of the end mill cutter, sothat the end mill cutter 2 is rotated into the receiver opening 7 in ahelical motion until the end mill cutter 2 has reached a stop.

FIG. 2 schematically illustrates a tool holder 1 in a sectional view, inwhich the end mill cutter 2 is completely clamped in. The end millcutter 2 is disposed up to its stop with its cylindrical shaft 11 in thereceiver opening 7. Thus, the ball 4, which is supported by the threadedpin 9, engages the locking groove 13 or 14. In this graphic sectionalview, the cylinder shaft 11 is press fitted in the receiver opening 7,this means, the induction coil (not shown in the drawing) is turned offand the shrink fit chuck of the tool holder 1 is cooled down and shrunkback to its original size. As clearly visible in FIG. 2, an axialmovement of the end mill 2 along the rotation axis 3 cannot beperformed, since the ball 4 is located in the ball shaped locking groove13 or 14 in the cylinder shaft 11, so that a movement along the rotationaxis 3 is blocked. Thus, the interaction between the ball 4 and thelocking groove 13 or 14 is depicted in the form of a lock. In order toremove the end mill 2 cutter from the tool holder 1, the end mill 2after switching on the induction coil only has to be rotated against therotation direction 15 (re. FIG. 1), and pulled in axial direction alongthe rotation axis 3 out of the tool holder 1.

In the subsequent figures, viable embodiments are illustrated, showinghow the pullout preventer is configured in other state of the artclamping tools.

FIG. 3 shows a typical draw-in collet chuck with cap nut with thepullout preventer with the locking grooves and balls in a schematicsectional view.

FIG. 4 shows a high precision chuck with the pullout preventer accordingto the invention through locking grooves and balls.

FIG. 5 shows a typical hydraulic expansion chuck with the pulloutpreventer according to the invention through locking grooves and ballsin a schematic sectional view.

FIG. 6 shows a tool holder provided as shrink fit chuck in a schematicsectional view, where the end mill cutter is bolted to the tool througha thread 16. Through this threaded connection, which is configured witha left pitch direction for a left grooved tool, and a right pitchdirection for a right grooved tool, an axial pullout prevention of thetool from the tool holder is implemented.

FIG. 7 shows a shrink fit chuck in a schematic sectional view withlocking elements in the form of balls 4, which are held in therespective support bore holes 5 with threaded pins 9. The threaded pin 9thus comprises a blunt face.

FIG. 8 shows a shrink fit chuck with locking elements configured asballs 4 in a purely schematic sectional view, where the balls are heldin the support bore holes 5 by threaded pins 9. The threaded pin 9comprises a recess 17 on the face receiving the ball 4. The recess 17 isconfigured as a dead hole or e.g. configured as bushing with an interiorhexagonal shape corresponding to the diameter of the ball.

FIG. 9 shows a shrink fit chuck with locking elements provided as balls4 in a purely schematic sectional view, where the balls are held in thesupport bore holes 5 by alignment pins 18. Due to the press fit betweenthe alignment pin 18 and the support bore hole 5, the locking elementsprovided as balls 4 are fixated in their position.

FIG. 10 shows a shrink fit chuck with one-piece locking elements 19 in apurely schematic sectional view. The locking element 19 is a threadedpin, which comprises a semi-spherical head 20 at one of its faces.

FIG. 11 shows a shrink fit chuck with a one-piece locking element 19 inthe support bore holes 5 in a purely schematic view. The one-piecelocking elements 19 are alignment pins, which are connected to theshrink fit chuck through a press fit. The one-piece locking elements 19comprise a semi-spherical head 20 on one of their faces.

FIG. 12 shows a shrink fit chuck with locking elements in the form ofballs 4 in a purely schematic sectional view. The balls 4 are supportedin a ball retainer 21. Thus, the ball retainer 21 is disposed at thebottom of the receiver opening 7. Adjacent thereto, there is a sleeve22. In the retainer 21, the balls 4 are recessed, which are pressed bythe retainer to the radial outside. Thus the balls 4 are thus pressedagainst a shoulder, which is disposed between the receiver opening 7 anda rotation relief at the end of the receiver opening 7. The balls 4 canbe radially supported at said shoulder. When the tool is shrunk in, theballs 4 are supported towards the inside and can secure the tool 2 aswell as the sleeve 22 against an axial pullout.

FIG. 13 shows a shrink fit chuck with balls 4 in a purely schematicsectional view, where the balls are disposed in a sleeve 22 in the leftsection of the sleeve and in the receiver opening 7. The left section ofthe sleeve 22 thus functions as a ball retainer for the balls 4. Thesupport bore holes 5 for the balls 4 in the sleeve 22 comprise a smallerdiameter with reference to the inner cylindrical circumferential surfaceof the sleeve 22, than the diameter of the balls or the diameter of thesupport bore hole. Thus, the balls 4 can protrude into the inner cavitybut they cannot fall in. The sleeve 22 is either shrunk or pressed intothe chuck.

FIG. 14 shows a shrink fit chuck with balls 4 in a sleeve 22 in a purelyschematic sectional view. The sleeve 22 is connected to the sleevesection 6 by a weld 23. The weld of the sleeve 22 with the shrink fitchuck can thus be performed in spots in sections or annular as a closed-or Y-weld.

FIG. 15 shows a shrink fit chuck with balls 4 in a sleeve 22 in a purelyschematic sectional view. In this embodiment, the sleeve 22 is fixatedto the tool holder by threaded pins 24. Thus, the threaded pins 24 e.g.comprise a conical cap. Certainly also other embodiments, like e.g. aball head, are possible. The sleeve 22 comprises indentations 25corresponding to the face configuration of the threaded bolts 24, wheresaid indentations are configured corresponding to the face capconfiguration of the threaded pins 24. In the present embodiment, saidindentations 25 are configured conical. In order to fixate the sleeve 22at the tool holder, at least one threaded pin 24 with a conical faceconfiguration or with an overall conical configuration is necessary.Preferably, three, in particular four threaded bolts for fixating thesleeve 22 are disposed at the tool holder.

FIG. 16 shows a shrink fit chuck with the locking elements provided asballs 4, disposed in the sleeve 22, in a purely schematic sectionalview. The sleeve 22 is thus configured thicker than in the precedingfigures. Therefore, the sleeve 22 is slotted (not shown in the drawing).In this embodiment, the sleeve 22 is also connected to the tool holderby balls. Thus, locking grooves 27 corresponding to the balls aredisposed in the left portion of the sleeve 22, where said grooves have aprofile corresponding to the balls. The same way as the tool is axiallyfixated in the shrink fit chuck through the interaction of lockingelements and locking grooves, the sleeve 22 is axially fixated throughballs 26 as locking elements with locking grooves 27 in the outercircumferential surface of the sleeve 22. The balls 26 are thus disposedin support bore holes 28, which in turn connect threaded pins 29 amongstone another by a thread. Also in this case, the support bore hole 28comprises a smaller diameter in the inner portion in the directiontowards the receiver opening 7, than the diameter of the support, whichcorresponds to the ball diameter of the ball 26. Thus, the balls 26cannot fall into the interior cavity, but they protrude into it.

FIG. 17 shows a shrink fit chuck with an axial pullout preventeraccording to FIG. 2 in a purely schematic sectional view. Additionally,the tool holder comprises a conical spring 30, which is disposed betweenthe face side 12 of the cylinder shaft 11 of the end mill cutter 2 andthe bottom 31 of the receiver opening 7. The compression spring providedas a conical spring 30 thus presses onto the face 12 of the end mill 2cutter in the direction of the rotation axis 3 out of the tool holder 1.Thus, a possible clearance or manufacturing tolerances of the lockinggrooves in the circumferential surface of the cylinder shaft 11 and therespective position of the balls 4 in the tool holder 1 are eliminated,in as far as the end mill cutter 2 is additionally locked in axialdirection by the force of the conical spring 3. Thus, also a smallclearance between the axial pullout preventer and the tool can beeliminated. Thus, there is no risk to additionally damage the cuttingedges of the tool during operation, due to small manufacturingtolerances.

FIG. 18 shows a shrink fit chuck with the locking elements in the formof balls 4 in a purely schematic sectional view. Herein, a pulloutprevention of the tool without clearance is performed after shrinking inthrough the use of a length adjustment screw 32, which is preferablymade of a rubber elastic material. Corresponding to the lengthadjustment screw 32, a corresponding inner thread 33 is formed in thetool holder. In FIG. 18, another embodiment for the path of the lockinggroove is shown. In this embodiment, the locking groove 34 is providedin the shape of an “L”, but starting at the face 12 of the cylindershaft 11. Thus, a quasi bayonet lock for an axial safety is provided asa pullout safety for the tool from the tool holder.

FIG. 19 shows a shrink fit chuck from FIG. 18 in a purely schematicsectional view, wherein an elastic element 35 is integrated therein,concentric to the length adjustment screw 32. In this case, the elasticelement 35 is preferably made of a rubber elastic material. The pulloutprevention without clearance is performed through the compression force,which is imparted through the length adjustment screw 32 to the elasticelement 35 through the face 12 to the end mill cutter 2.

FIG. 20 shows a shrink fit chuck with a minimum volume lubrication (MMS)in a purely schematic sectional view. The axial pullout prevention isperformed by locking elements 36, which are in turn provided as balls.Concentric to the rotation axis in the interior of the shrink fit chuck,there is a movable tube 37, which is the transfer piece for the minimumvolume lubrication. The tube 37 is pressed against the tool shaft (notshown in the drawing) due to the spring force of a coil spring 38. InFIG. 20, two possible end positions of the tube 37 are shown. Thecontact surface of the tube disposed on the right with the tool shaft isprovided conical in the shape of a radial tubular flange 39. The coilspring 38 is thus concentrically permeated by the tube 37. The coilspring 38 is disposed between the bottom 31 and the cone section shapedcircumferential surface of the tube 37 at the radial neck flange. FIG.21 illustrates the tangential disposition of the locking elements 36 inthe tool holder along the section line A-A of FIG. 20 in a purelyschematic sectional view. FIG. 22 shows an enlarged detail of FIG. 20,which is marked by a dashed line. In a radial neck flange 39 of the tube37, pass-through bore holes 40 are disposed, which extend from the innerdiameter of the tube 37 to the outer circumferential surface 41 of theradial tubular flange 39. Along the cylindrical circumferential surface41 of the radial tubular flange 39 of the tube 37, a concentric cylindersurface shaped recess 42 is disposed, whose width is preferably smallerthan the width of the cylindrical circumferential surface 41 of thetubular flange 39. Corresponding to the recess 42, an annular membrane43 formed as a section of an enveloping surface of a cylinder isdisposed, which is formed flush with the outer cylindricalcircumferential surface 41 of the tubular flange 39. The membrane 43 isthus preferably formed from a rubber elastic material. Said membrane 43along the circumferential surface 41 seals the tube 37 against the wallof the receiver opening 7 of the shrink fit chuck. The bore holes 40,which radially lead to the inside of the membrane 43, pass the airpressure onto the membrane 43, which is thus pressed against the wall 7of the bore hole. Through the pressure buildup, the membrane cambers inradial direction and thus attaches to the inner circumferential surfaceof the receiver opening 7 of the tool holder. Thus, the tube 37 issecured as a transfer piece for the minimum volume lubrication againstaxial displacement. Through the movable tube 37, the lubricant mist canbe conducted to the tool without loss.

What is claimed is:
 1. A tool system comprising: a tool with arotational axis about which the tool rotates during operation and a toolshaft with a cylindrical surface; wherein at least one locking groove isdisposed in the cylindrical surface of the tool shaft; wherein the atleast one locking groove has a first terminal end, a second terminal endthat is separated from the first terminal end, a centreline extendingbetween the first and second terminal ends, and a curved portion locatedbetween the first and second terminal ends; wherein the portion of thecentreline associated with the curved portion is curved and has pointsthat are each defined by: (a) a non-zero axial value in the direction ofthe rotational axis with the first terminal end having a zero axialvalue, (b) a non-zero azimuthal value with the first terminal end havinga zero azimuthal value and (c) a non-zero radius value with the firstterminal end also having a non-zero radius value; and a tool holder witha clamping chuck for receiving the tool shaft; wherein the clampingchuck has an interior surface that defines an interior cavity forreceiving a tool and at least one locking element with a locking surfacefor engaging the at least one locking groove, the locking surface atleast partially projecting from the interior surface of the clampingchuck; wherein the at least one locking element is adapted, when thetool is operatively located in the clamping chuck, to interact with theat least one locking groove of the tool in a form locking manner toprevent axial migration of the tool out of the tool holder.
 2. A toolsystem, as claimed in claim 1, wherein: the non-zero radius valuesassociated with points on the curved portion are substantially constant.3. A tool system, as claimed in claim 1, wherein: in a plan view of thelocking groove, the non-zero axial values and non-zero radial valuesassociated with points on the portion of the centreline associated withthe curved portion of the locking groove appear as a straight line.
 4. Atool system, as claimed in claim 1, wherein: in a plan view of thelocking groove, the non-zero axial values and non-zero radial valuesassociated with points on the portion of the centreline associated withthe curved portion of the locking groove define a curve.
 5. A toolsystem, as claimed in claim 1, wherein: the locking groove includes astraight portion located between the first and second terminal ends. 6.A tool system, as claimed in claim 5, wherein: points on the portion ofthe centreline associated with the straight portion have a substantiallyconstant azimuthal value.
 7. A tool system according to one of thepreceding claims, wherein: the at least one locking element and the atleast one locking groove are configured at least partially as a ballhead.
 8. A tool system according to one of the preceding claims,wherein: the clamping chuck is one of: (a) a draw in collet chuck, (b) ahigh precision chuck, (c) a hydraulic expanding chuck, and (d) a shrinkfit chuck.
 9. A tool system according to one of the preceding claims,wherein: the tool, in addition to the at least one locking groove,comprises one of: (a) a second locking groove and (b) a second, third,and fourth locking groove.
 10. A tool system, as claimed in claim 9,wherein: the locking grooves are disposed in the cylindrical surface ofthe tool shaft, where the locking grooves each start from a face of thetool and extend to at least one partial section of the tool shaft.
 11. Atool system according to one of the preceding claims, wherein: thecentreline associated with each of the locking grooves is one of thefollowing: (a) helical, (b) L-shaped, (c) comprised of a straightportion and a curved portion.
 12. A tool system according to one of thepreceding claims, wherein: when the centreline of one of the lockinggrooves includes a helical shape, the centreline has: (a) a left pitchdirection for a tool with a left groove and (b) a right pitch directionfor a tool with a right groove.
 13. A tool system according to one ofthe preceding claims, wherein: the shaft of the tool comprises an outerthread at its end, where the outer thread has: (a) a left pitchdirection for a tool with a left groove and (b) a right pitch directionfor a tool with a right groove, and the tool holder comprises an innerthread corresponding to the outer thread.
 14. A tool system, as claimedin claim 9, further comprising: an additional locking element for eachadditional locking groove beyond the at least one locking groove; thelocking elements and the locking grooves are disposed at the same angle.15. A tool system according to one of the preceding claims, wherein: thelocking elements are disposed in the tool holder in a plane that isperpendicular to the rotational axis of the tool when the tool isoperatively located in the clamping chuck.
 16. A tool system accordingto one of the preceding claims, wherein: each of the locking elementscomprises at least one of: (a) a ball, (b) a pin, (c) a bolt, and (d) athreaded pin, which each locking element having a locking surface withat least a partially ball shaped convex surface.
 17. A tool systemaccording to one of the preceding claims, wherein: each of the lockingelements in the tool holder is preferably made of stainless steel alloyand the partially ball head shaped convex face of the locking element ishardened.
 18. A tool system according to one of the preceding claims,wherein: each locking element is supported in a support bore hole in thetool holder, where the support bore hole extends continuously from anouter circumferential surface to the interior surface of the toolholder, and where each locking element is disposed one of: (a)perpendicular to the rotational axis of the tool holder and (b)tangentially adjacent to an interior surface of the tool holder.
 19. Atool system according to one of the preceding claims, wherein: each ofthe locking elements is held in a support bore hole using one of: (a) athreaded pin, (b) a press fit, and (c) an exterior thread, which isconfigured corresponding to the inner threads configured in the supportbore hole.
 20. A tool system according to one of the preceding claims,wherein: each of the locking elements situated in a support bore holereaches with a locking surface that includes a ball head shaped surfaceat least partially into the interior cavity of the tool holder.
 21. Atool system according to one of the preceding claims, wherein: each ofthe locking elements includes a ball that is held in the tool holder ina ball retainer, where the support bore holes for the balls of the ballretainer comprise a smaller diameter with reference to the inside thanthe support bore hole diameter.
 22. A tool system according to claim 21,wherein: the tool holder comprises at least one ball retainer in theinterior of the tool holder, wherein the ball retainer is a separatecomponent, machined into a sleeve, or a sleeve comprising a ballretainer, where the sleeve is pressed in, shrunk in, welded to the toolholder, held by threaded pins in an interlocking manner, and/or fixatedat the sleeve by locking elements and locking grooves.
 23. A tool systemaccording to one of the preceding claims, wherein: the tool holderincludes a force imparting element to reduce clearance, the forceimparting element including at least one of: (a) a compression spring,(b) a conical spring, (c) a coil spring, (d) a disk spring, (e) springpackets, and (f) rubber elastic elements.
 24. A tool system according toone of the preceding claims, wherein: the tool holder includes a chuckwith minimum volume lubrication held without clearance in axialdirection, where a transfer piece for the minimum volume lubricationcomprises at least one pass-through bore hole in the conical radialflange portion, a radial flange of the transfer piece comprises a radialrecess along a cylindrical enveloping surface, wherein correspondingthereto, a cylinder enveloping surface section shaped annular membraneis embedded in a form locking and flush manner, so that it touches,preferably configured from rubber elastic material, where thepass-through bore holes extend radially from the inner cavity of thetransfer piece to the membrane.
 25. A tool for use in a system accordingto claim 1, wherein: the tool comprises the features of one or plural ofthe preceding claims relating to the tool.
 26. A tool holder for use ina system according to claim 1, wherein: the tool holder comprises thefeatures of one or plural of the preceding claims relating to the toolholder.
 27. A tool system comprising: a tool holder with a clampingchuck for receiving a tool shaft of a tool; wherein the clamping chuckhas an interior surface that defines an interior cavity for receiving atool, the clamping chuck having at least one locking groove disposed inthe interior surface; wherein the at least one locking groove has afirst terminal end, a second terminal end that is separated from thefirst terminal end, a centreline extending between the first and secondterminal ends, and a curved portion located between the first and secondterminal ends; wherein the portion of the centreline associated with thecurved portion is curved and has points that are each defined by: (a) anon-zero axial value in the direction of the rotational axis with thefirst terminal end having a zero axial value, (b) a non-zero azimuthalvalue with the first terminal end having a zero azimuthal value and (c)a non-zero radius value with the first terminal end also has a non-zeroradius value; and a tool with a rotational axis about which the toolrotates during operation, a tool shaft with a cylindrical surface, andat least one locking element at least partially projecting from thecylindrical surface and adapted, when the tool is operatively located inthe clamping chuck, to interact with the at least one locking groove ofthe tool holder in a form locking manner to prevent axial migration ofthe tool out of the tool holder.
 28. A tool system, as claimed in claim27, wherein: the non-zero radius values associated with points on thecurved portion are substantially constant.
 29. A tool system, as claimedin claim 27, wherein: in a plan view of the locking groove, the non-zeroaxial values and non-zero radial values associated with points on theportion of the centreline associated with the curved portion of thelocking groove appear as a straight line.
 30. A tool system, as claimedin claim 27, wherein: in a plan view of the locking groove, the non-zeroaxial values and non-zero radial values associated with points on theportion of the centreline associated with the curved portion of thelocking groove define a curve.
 31. A tool system, as claimed in claim27, wherein: the locking groove includes a straight portion locatedbetween the first and second terminal ends.
 32. A tool system, asclaimed in claim 31, wherein: points on the portion of the centrelineassociated with the straight portion have a substantially constantazimuthal value.
 33. A tool system according to one of the precedingclaims 27-32, wherein: the at least one locking element and the at leastone locking groove are configured at least partially as a ball head. 34.A tool system according to one of the preceding claims 27-33, wherein:the clamping chuck is one of: (a) a draw in collet chuck, (b) a highprecision chuck, (c) a hydraulic expanding chuck, and (d) a shrink fitchuck.
 35. A tool system according to one of the preceding claims 27-34,wherein: the tool holder, in addition to the at least one lockinggroove, further comprises one of: (a) a second locking groove and (b) asecond, third, and fourth locking groove.
 36. A tool system, as claimedin claim 35, wherein: the locking grooves are disposed in the interiorsurface of the clamping chuck, where the locking grooves each start froma face of the tool and extend to at least one partial section of thetool shaft.
 37. A tool system according to one of the preceding claims27-36, wherein: the centreline associated with each of the lockinggrooves is one of the following: (a) helical, (b) L-shaped, (c)comprised of a straight portion and a curved portion.
 38. A tool systemaccording to one of the preceding claims 27-37, wherein: when thecentreline of one of the locking groove includes a helical shape, thecentreline has: (a) a left pitch direction for a tool with a left grooveand (b) a right pitch direction for a tool with a right groove.
 39. Atool system according to one of the preceding claims 27-38, wherein: theshaft of the tool comprises an outer thread at its end, where the outerthread has: (a) a left pitch direction for a tool with a left groove and(b) a right pitch direction for a tool with a right groove, and the toolholder comprises an inner thread corresponding to the outer thread. 40.A tool system, as claimed in claim 35, further comprising: an additionallocking element for each additional locking groove beyond the at leastone locking groove; the locking elements and the locking grooves aredisposed at the same angle.
 41. A tool system according to one of thepreceding claims 27-40, wherein: the locking elements are disposed inthe tool in a plane that is perpendicular to the rotational axis of thetool.
 42. A tool system according to one of the preceding claims 27-41,wherein: each of the locking elements comprises at least one of: (a) aball, (b) a pin, (c) a bolt, and (d) a threaded pin, which each lockingelement having a locking surface with at least a partially ball shapedconvex surface.
 43. A tool system according to one of the precedingclaims 27-42, wherein: each of the locking elements in the tool ispreferably made of stainless steel alloy and the partially ball headshaped convex face of the locking element is hardened.
 44. A tool systemaccording to one of the preceding claims 27-43, wherein: each lockingelement is supported in a support bore hole in the tool and where eachlocking element is disposed one of: (a) perpendicular to the rotationalaxis of the tool and (b) tangentially adjacent to the cylindricalsurface of the tool.
 45. A tool system according to one of the precedingclaims 27-44, wherein: each of the locking elements is held in a supportbore hole using one of: (a) a threaded pin, (b) a press fit, and (c) anexterior thread, which is configured corresponding to the inner threadsconfigured in the support bore hole.
 46. A tool system according to oneof the preceding claims 27-45, wherein: each of the locking elementssituated in a support bore hole reaches with a locking surface thatincludes a ball head shaped surface at least partially beyond thecylindrical surface of the tool.
 47. A tool system according to one ofthe preceding claims 27-46, wherein: each of the locking elementsincludes a ball that is held in the tool in a ball retainer, where thesupport bore holes for the balls of the ball retainer comprise a smallerdiameter with reference to the inside than the support bore holediameter.
 48. A tool system according to claim 47, wherein: the toolcomprises at least one ball retainer in the interior of the tool,wherein the ball retainer is a separate component, machined into asleeve, or a sleeve comprising a ball retainer, where the sleeve ispressed in, shrunk in, welded to the tool holder, held by threaded pinsin an interlocking manner, and/or fixated at the sleeve by lockingelements and locking grooves.
 49. A tool system according to one of thepreceding claims 27-48, wherein: the tool holder includes a forceimparting element to reduce clearance, the force imparting elementincluding at least one of: (a) a compression spring, (b) a conicalspring, (c) a coil spring, (d) a disk spring, (e) spring packets, and(f) rubber elastic elements.
 50. A tool system according to one of thepreceding claims 27-49, wherein: the tool holder includes a chuck withminimum volume lubrication held without clearance in axial direction,where a transfer piece for the minimum volume lubrication comprises atleast one pass-through bore hole in the conical radial flange portion, aradial flange of the transfer piece comprises a radial recess along acylindrical enveloping surface, wherein corresponding thereto, acylinder enveloping surface section shaped annular membrane is embeddedin a form locking and flush manner, so that it touches, preferablyconfigured from rubber elastic material, where the pass-through boreholes extend radially from the inner cavity of the transfer piece to themembrane.
 51. A tool for use in a system according to claim 27, wherein:the tool comprises the features of one or plural of the preceding claims27-50 relating to the tool.
 52. A tool holder for use in a systemaccording to claim 27, wherein: the tool holder comprises the featuresof one or plural of the preceding claims 27-50 relating to the toolholder.